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© Andigilog, Inc. 2006
www.andigilog.com
October 2006 - 70A06010
aSC7621
0
10
20
30
40
50
60
1
23
4
56
78
9 10 11 12
Figure 11 Representation of What Temperature Is Passed to the aSC7621 Auto Fan Control with (green)
and without (red dashed) Spike Smoothing
Spike Smoothing
Time
ZNn-[2:0]
35 seconds
000
17.6 seconds
001
11.8 seconds
010
7.0 seconds
011
4.4 seconds
100
3.0 seconds
101
1.6 seconds
110
0.8 seconds
111
Table 23 Spike Smoothing for ZN1 to ZN4
PWM Action
Off/Min Bit
At 0% duty below LIMIT
0
At Min PWM Duty below LIMIT
1
Table 24 PWM Output Below Limit Depending on Value of Off/Min
Register 64-66h: Minimum PWM Duty Cycle
Register
Address
Read/
Write
Register
Name
Bit 7
(MSB)
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
(LSB)
Default
Value
Lock
64h
R/W
Fan 1 PWM
Minimum
7
6
5
4
3
2
1
0
80
X
65h
R/W
Fan 2 PWM
Minimum
7
6
5
4
3
2
1
0
80
X
66h
R/W
Fan 3 PWM
Minimum
7
6
5
4
3
2
1
0
80
X
This register specifies the minimum duty cycle that the PWM will output when the measured temperature reaches the
Temperature LIMIT register setting.
This register becomes Read-only when the Ready/Lock/Start/Override register Lock bit is set. Any further attempts to write
to this register shall have no effect.